I've had some issues w/ light seals on the Nikons myself. Usually, it's the flat seal where the door closes at the hinge. Or, just put a piece of tape over it once you've closed the camera. My FT2 has a bad (missing) seal there, and several years ago I simply cut a piece of electrical tape the right length and stuck it on there, meaning to do the seals later. I still haven't gotten around to doing that, and the door opens fine w/ the tape, so it's on the back-burner list. Because the camera and the tape are both black, I always forget it's even there.

A trip to Malwart got me a $2 roll of black knitting twine for the horizontal body seals, and judging from the size of the roll, it should last me about 50 years. Not that I'll be here then, but still, it's a cheap way to go, and has worked well on every camera I've used it on so far.